This informative publication is intended as a working guide for anyone undertaking the hydrodynamic modeling of river systems.
By way of illustration, it uses the Juru River in Malaysia as an example river and Wallingford Software’s InfoWorks River Simulation (RS) software as the example hydrodynamic modeling tool.
The publication describes general issues related to the hydraulic analysis of river systems in Malaysia, namely:
- Flooding: flood prone areas, damage to the country
- Pollution: the number of polluted rivers is increasing
- Erosion and sedimentation: effects from development, such as land clearing, is causing instability to the river regime
The publication goes on to describe how to solve these key issues and concludes that it is important to understand the problems thoroughly before attempts are made to address them. This point might appear obvious to the water engineer or modeler but in my experience is frequently overlooked by decision-makers.
In order to understand these key issues the authors argue in favor of hydrodynamic modeling. The authors explain that estimating water levels during flooding conditions is a complex computation. However, this can be achieved effectively using the St Venant equation, which describe the flow under various influences and is modeled using the InfoWorks RS model.
In order to learn how to model a river, it is preferable, we believe, to do this by undertaking a modeling exercise. The authors concur, and this book provides a worked example based on the Juru River and the InfoWorks RS software. The Juru River was selected due its small size and because of the availability of data describing the river network.
The Juru River has various tributaries that experience flood and pollution problems. These are caused by a variety of factors including uncontrolled development, poor maintenance and under-designed structures. Pollution sources include industries, pig farms and illegal rubbish dumping.
The first chapter of the book contains some photographs at various locations that provide the reader with a visual indication of the state of the river and the flooding problems experienced. It then goes on to explain about the data required to develop a river model including the data sources that are required. A a step by step explanation guides the reader in the development of a river model including a base map and river cross section, the boundary condition which includes the rainfall and tidal data and river structures This also includes simulation methods and tips to ensure the model runs smoothly.
As calibration is one of the major issue in river modeling the author elaborates on how to use a simple technique to produce a good calibration such as improving the river section to cater for the extent of flooding.
The last chapter explains the usage of the river model. The book shows a simple technique for studying the impact on flood risk due to urban development and river improvement work. The appendix explains some processes that engineers need to check while doing survey work for the purpose of river modeling.
In summary, the book provides a comprehensive worked example of a river modeling exercise based on the Juru River and the InfoWorks RS software. A CD containing all the necessary river modeling data is also available. This book should prove valuable to all river modelers, but particularly those working in areas of rapid urbanization.
‘Pendekatan Awal Menggunakan InfoWorks RS’ is published by National Hydraulics Research Institute of Malaysia (NAHRIM) (ISBN 983-42905-0-0).